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Biomedical subjects

M Kanazawa

Publications and source records attributed to M Kanazawa.

At least 307 records · Page 17Linked to original sources
PubMed1980

[Gastrointestinal hormones during pregnancy--immunoreactive secretin and gastrin in serum and fetal tissue (author's transl)].

The concentrations of immunoreactive secretin (S) and gastrin (G) in maternal peripheral vein (MV) during pregnancy and MV, umbilical artery (UA) and umbilical vein (UV) at delivery and fetal tissue of 19, 23 weeks of gestation obtained after therapeutic abortion were measured by specific radioimmunoassay. S-specific antisera was generated in rabbits against highly purified synthetic S. Newly synthesized S analog (Tyr1)-S was indicated by enzymic method. The radioimmunoassay of S was performed by double antibody method using synthetic S as standard. G was measured by RIA kit (Dainabot radioisotope Lab.). The sensitivity of the assays for S and G was 50 pg/ml. The fetal tissue were extracted by water-boiling method and purified by gel filtration on Sephadex G-25 column. The S levels in MV increase as gestational age advances and reach to the maximum levels of 248 +/- 150 pg/ml, while no increase tendency was noticed in G levels. The S levels in MV, UA and UV at delivery (n = 18) were 307 +/- 158 pg/ml, 460 +/- 166 pg/ml and 424 +/- 126 pg/ml, respectively. The S levels in cord blood is statistically higher than that in MV (p less than 0.05). The G levels in MV, UA and UV were 67 +/- 22 pg/ml, 101 +/- 63 pg/ml and 91 +/- 38 pg/ml. The differences of the values between MV and cord blood are significant (p less than 0.05). S like material in fetal upper gastrointestinal tracts was found high in concentration. The extract of fetal duodenum showed a displacement curve paralleled to that of the standard S. In addition, relatively high concentration of immunoreactive S was found in cerebral cortex obtained from fetus of 23 weeks of gestation. G concentration in fetal tissue was also demonstrated. The evidence of immunoreactive S and G in fetal blood and fetal gastrointestinal tracts was reported. These results may be of importance to provide the information in understanding the physiology of the fetus.

Female↗
PubMed1976

[Effect of oral contraceptive on the pituitary and plasma L.H. levels and on the hypothalamic LH-RH level (author's transl)].

The effects of the oral contraceptive on the pituitary content and plasma level of LH and the hypothalamic LH-RH level were investigated in 16 adult female rabbits. The oral contraceptive preparation, Sophia-C (Norethindrone 2mg + Mestranol 0.1 mg), as administered orally by a stomach tube each day for 7 days in 8 adult female rabbits. At the end of the treatment, the rabbits were bled from the abdominal aorta into heparinized syringes and the plasma was separated. The stalk median eminences were excised. All the materials were stored in -80 degrees C until assayed. Plasma level and the pituitary content of LH and the hypothalamic LH-RH were measured by radioimmunoassay. All the dose response curved were drawn using logitlog transformation. Radioimmunoassay procedures for LH was described in detail elsewhere. Purified rabbit LH for iodination (125-I) and strandard were prepared by T. Makino and R.O. Greep, at Research Laboratories for Human Reproduction, Harvard Medical School, Boston, U.S.A. The starting B/T was 25% at the final dilution of the antibody of 1/20,000. Minimal detectable quantity was about 40 pg/tube. The 50% intercepts were approximately 460 pg/tube. Radioimmunoassay procedures for LH-RH were performed according to the method described by Arimura et al. Antiserum against synthetic LH-RH was kindly supplied to us by Drs. A. Arimura and A.V. Schally, New Orleans, U'S.A. The synthetic LH-RH was kindly supplied to us by Dr. N. Yanaihara. The starting B/T ratio was 29% at the final dilution of the antibody of I/17,500. Minimal detectable quantity was about 40pg/tube and the 50% intercepts were 150pg/tube. It has been assumed that oral contraceptive drugs exert their action by blocking the hypothalamic LH-RH, resulting in a depression of the plasma level of LH, because plasma level of LH returned to the normal level when LH-RH was administered intravenously even while oral contraceptive steroids were given continuously. However, these findings concerning the site of action of the drugs furnished only indirect evidences. The possibility of a direct inhibitary effect of these steroids on the anterior pituitary cannot be ruled out. Administration of 2mg of Norethindrone and 0.1mg of Mestranol significantly depressed both the pituitary content and the plasma level of LH. On the other hand, they significantly increased the hypothalamic LH-RH level. Those findings strongly suggested the direct action of this drug on the anterior pituitary in the female adult rabbits. Detailed mechanisms on how the hypothalamic LH-RH was increased were not known in this experiment, further investigations are now in progress.

Animals↗
PubMed1976

Effects of Adalat (nifedipine) on left ventricular hemodynamics in angina pectoris: comparative study with propranolol.

The hemodynamic effects of nifedipine and propranolol administered intravenously were studied in 17 patients with angina pectoris. Nine patients received nifedipine and eight received propranolol. The hemodynamic parameters were compared at rest and during supine bicycle exercise at work loads known to produce angina. Exercise-induced angina improved in four out of nine patients following nifedipine and in one out of eight patients following propranolol. Nifedipine significantly reduced the increment of left ventricular end-diastolic pressure and Vmax during exercise. Intravenous propranolol significantly suppressed the increment of heart rate, max dp/dt, tension time index, and Vmax during exercise. Although the exact mode of action of nifedipine remains uncertain, it is suggested that it decreases myocardial oxygen requirements primarily through a reduction of left ventricular volume, whereas propranolol suppresses the positive chronotropic and inotropic responses of the heart muscle to exercise.

Adult↗